This invention relates to releasable locking devices, and in particular to a locking device for acting between a movable table and a fixed table of a circular saw.
Circular saws, in which a saw blade, driven by a motor, is hingedly connected to a base table for cutting workpieces situated on the base table, are well known. It is also known for a base table to include a round saw table rotatably received in the middle of a fixed table. The round table sometimes has an extension arm received in a segmental recess of the fixed table.
The round table and extension arm (if included) have a slot into which the blade of the circular saw plunges after cutting a workpiece received against a guide fence fixed to the base table. Plunging of the blade is achieved by pivoting of the blade housing. Mitre cuts can be made with such prior art saws by first rotating the round table, and hence the saw blade, with respect to the fixed table and fence.
Although a prior art circular saw as described above works well, the freedom of the pivot necessary to allow the round table to rotate to different positions can be a potential source of positional error during the cutting of a workpiece. This is particularly relevant when considering mitre angles, wherein a few degrees of error can make a substantial difference to the end result.